Mineral concentration



Patented Dec. 5, 1944 4 menu. CONCENTRATION.

Ludwig Jacob Christmann, Yonkers, N. Y., Davld Walker Jayne, Jr., Old Greenwich, Conn and, Stephen Edward Erickson, Calumet, Minn., as signors to American Cyanamid Company, New York, N. Y., a corporationoi' Maine No Drawing. Application September 4, 1941,

Serial No. 409,530.

14 Claims. (Cl. 209166) The present invention relates to mineral concentration. More particularly it relates to a new class of reagents for selectively separating acidic minerals from ore materials.

Still more particularly it relates to the use of the reaction products of polyalkylene polyamines with fatty acids or fatty acid glycerides or other esters and the substantially water soluble salts of such products, as promoters or collectors for acidic minerals in froth flotation, film flotation, Stratification, agglomeration, tabling, and related mineral separation processes. While the present invention is not limited to any particular ore concentrating process utilizing differential surface wettability principles, or to any particular ore, its most lmportantfield of usefulness is in connection with froth flotation processes of separating silica or silicate minerals, such as mica from nonmetallic ores including limestone, bauxite bary-' tes, ilmenite, calcite, and the like, and especially phosphate minerals.

A recent development in processes for the concentration of ores is one in which the so-called "cationic reagents are used as promoters or collectors for acidic silicious gangues to effect a separation from the ore values. The use of these cationic reagents has resulted in a more economical and eflicient method of recovering the ore values from a number of ore materials and particularly in connection with phosphate bearing ores in which the silicious gangue is floated away from the phosphate minerals.

In accordance with this invention natural ores or artificial materials comprising mixtures of acidic minerals with other mineral constituents positively charged surface active ions'h'ad a strong afllnity for anionic oracidic minerals, and hence they are sometimes loosely referred to in the art as cationic reagent."

We have found that it is not necessary to the present invention to use salts as similar results are obtained with the condensation products themselves, provided satisfactory dispersion and distribution is effected. The present invention is accordingly not intended to be limited in any way tov the use of silica promoter which is highly ionized. The interaction between the surface of the silica and the promoter does not appear to be tied up exclusively with the presence of actual ions. The theory advanced in the prior art does not therefore appear to be correct as applied to silica flotation, or at least it does not appear to be a necessary factor in the present invention. We do not wish to advance any definite theory of action in silica flotation and the present invention is not intended to be limited to any particular theory of the so-called cationic reagent.

The compounds that have been found to have a selective filming attraction for acidic minerals and are useful in carrying out the present invention include broadly the reaction products of polyalkylene polyamines with fatty acids or fatty acid glycerides or other esters and salts of these reaction products. The general method of preparing the reagents employed in carrying out the present invention comprises heating a fatty acid,

fatty acid glyceride, or the like with a polyalky-' are subjected to a separation or concentration process in the presence of a promoter for the acidic ore minerals, said promoter being the condensatOn products of polyalkylene polyamines and fatty acids or the salts of such products, to effect a separation of the acidic minerals from the other ore constituents.

The present invention relates to an entirely new class of promoting .or collecting reagents for acidic minerals. These compounds are surface active compounds and are basic in character. These new reagents are promoters for negatively charged or acidic ore materials. The promoter action will, of course, vary with different acidic ore materials and with the different polyalkylene polyamine fatty acid condensation products or salts used. In the past various theories have been advanced as to the manner in which some acidic silicious promoters worked, one of which was that lene polyamine at a temperature of from 250-270 C. or higher until the reaction is complete.

In preparing our reagents we have not definitely determined what constitutes their chemical structure and we prefer therefore to describe them by their method of preparation. A suitable method for preparing them comprises heating a mixture of a polyalkylene polyamine and a higher fatty acid or a higher fatty acid ester at a temperature above 250 C.

In our co-pending application Serial No. 326,- 952, of which the present application is in part a continuation, we are claiming the use of similar products obtained by heating to not over 250 C. and preferably not over 180 to C. At these lower temperatures the products obtained are essentially higher acyl amides of the polyalkylene polyamines. In these reactions at the lower temperatures only one mol-of water is liberated for every mol of fatty acid used. In the same process, when a fatty acid ester such as the glyceride, is used, one molof an alcohol (glycerol) is liberated rather than water. Regardless of whether or not a fatty acid or a fatty acid glyceride is employed at these lower temperatures, an acyl amide is produced which, upon hydrolysis, regenerates a moi of fatty acid for every mol of fatty acid or fatty acid. equivalent used. In the present application, wherein the reaction is carried out at a temperature in excess of 250 C., the products obtained are different from those obtained and claimed in our parent application. That they are different may be demonstrated by the following illustrations using diethylene triamine as a typical polyalkylene polyamine (R equals an alkyl radical containing 8 or more carbon atmos): t

B 1 11-0003 H|N(CH1):NH(CH:):NH|250:23):C.

N-CH| m-cm-Nn,

This product will not hydrolyze under conditions which cause hydrolysis of the product obtained by reacting the same substance at a temperature less than 250 C. In the parent application the products produced by heating at temperatures slightly less than 250 C. are probably mixtures of the acyl amides and the compounds described in the above reaction, since a mol and a fraction of a mol of water are liberated in some instances.

N-CH,

Hr-C Hr-NH-C OR In this reaction where two mols of fatty acid are employed it is noted that there is an amide linkage and the product can be partially saponifled or hydrolyzed to yield one mol of the fatty acid employed. The other mol of the fatty acid, however, is still combined and cannot be removed by hydrolysis.

a R-C o-o-cm orn-om-Nn-co-a lln Reaction 3 where one mol of a fatty acid glyceride is reacted with three mols of diethylene triamine at a temperature in excess of 250 C. three mols of water are liberated in the reaction, i. e., one for each molecular equivalent of fatty acid present, and during the same reaction one mol of glycerol is liberated. The product obtained in other respects has the same properties ascsma action 4, a product is obtained having the prop erties of that obtained by Reaction 2 and can be partially saponifled to liberate one mol of the two mols of fatty acid combined with each mol of diethylene triamine.

In all the reactions carried out at a temperature in excess of 250 C. one extra mol of water per mol of fatty acid or fatty acid equivalent used in the reaction is liberated as compared to the amount liberated at a temperature lower than the 250 C.

When other polyalkylene polyamines other than diethylene triamine are used similar reactions are believed to take place.

In order to more fully illustrate a satisfactory method for preparing our reagents the following specific examples are presented.

Example 1 A mixture of 215 g. (1 mol) of coconut oil fatty acids and 103 g. (1 mol) of diethylene triamine was heated to 260 C. with the liberation of 36 g. (2 mols) of water. The product was a brownish-yellow paste, dispersible in water, and clearly soluble in dilute acids to form soapy solutions.

Example 2 A mixture of 440 g. of coconut oil (equivalent to 2 mols of coconut oil fatty acids) and 103 g. (1 mol) of diethylene triamine was heated to 270 C. with liberation of 18 g. (1 mol) of water. The product was similar to that obtained in Example 1.

Example 3 A mixture of 456 g. (2 mols) of myristic acid and 103 g. (1 mol) of diethylene triamine was heated to 270 C. with the liberation of 54.0 g. (3 mols) of water. The product was a soft wax, clearly soluble in dilute acids to form soapy solu- 40 tions.

as that obtained in Reaction 1. When two mols of a fatty acid glyceride are reacted with three mols of diethylene triamine as illustrated in Re- Example 4 A mixture of 220 g. of coconut oil (equivalent to 1 mol of coconut oil fatty acids) and g. (1 mol) of a mixture of polyalkylene polyamines (containing approximately 50% diethylene triamine, 25% triethylene tetramine and 25% tetraethylene pentamine) was heated to 270 C. with the liberation of 18 g. (1 mol) of water. The product was similar to that obtained in Example 1.

When a higher polyalkylene polyamine, such as for example triethylene tetramine, tetramethylene pentamine, or a mixture of" polyalkylene polyamines are used, it is frequently necessary to heat to about 270 C. in order to produce the desired product. In some cases it may be necessary to employ temperatures as high as 300 C. in order to produce the desired product, In carrying out the condensation, the polyalkylene polyamine may be mixed with the higher fatty acid or higher fatty acid glyceride at room temperature or a low temperature and the mixture then heated until the desired temperature of from 250 to 300 C. is reached. If preferred, however, the higher fatty acid or glyceride may be heated to a temperature of from 250 to 300 C. and the polyalkylene polyamine likewise heated to a high temperature and the mixture brought about at this elevated temperature.

The compounds used in the present invention are not limited to those produced by reacting any particular ratio of the polyalkylene polyamine to mixtures which may contain an excess of either the polyalkylene polyamine or the fatty acid.

The molecular ratio of the fatty acid content in some cases may therefore be varied as desired.

The polyalkylene polyamines that may be employed for preparing our reagents may be represented by the following general formula:

distillation. When propylene chloride, butylene chloride, amylene chloride, and the like, are employed instead of ethylene chloride, the corresponding polyalkylene polyamines are obtained. The expression polyalkylene polyamine" 'employed in the claims therefore refers to and is intended to include any one of the polyamines referred to above or to a mixture of the above polyamines.

The compounds used in the present invention are usually homogeneous viscous pastes which will combine with acids such as formic, acetic, hydrochloric, and the like, to yield salts which are soluble in water. They may be used in flotation processes in the salts or the free base may be used provided satisfactory dispersion is obtained. Quaternary salts may be prepared by treatment with an alkylating agent such as an alkyL pr aralkyl halide, dialkyl sulfate, or the like.

Representative polyalkylene polyamines which may be employed in condensing with the fatty acids are diethylene triamine, dipropylene triamine, dibutylene triamine, triethylene tetramine. tetraethylene pentamine, or mixtures of any two or more of such polyamines either as relatively pure compounds or crude mixtures. In general they are polyamines, the different amino groups of which are separated from one another by a hydrocarbon radical containing from 2 to 12 carbon atoms. 7

Either the saturated, unsaturated, or hydroxy fatty acids may be employed for reacting with the polyamines, the preferred ones being those having at least nine carbon atoms, for example, lauric, palmitic, stearic, olei-c, ricinoleic, capric, myristic, mixtures of such acids and especially mixtures of the fatty acids obtained from the fats and oils of either vegetable or animal sources or their glycerides such as those in coconut oil, palm oil, palm kernel oil, cottonseed oil, corn oil, linseed oil, olive oil, peanut oil, fish oils, and the like, as well as talloel and naphthenic acid.

The reagents of the present invention are efiec tive promoters or collecting agents for acidic ore materials generally and said acidic materials may be either worthless gangue or valuable ore constituents. The most important use, however, is in connection with the froth flotation of silica from non-metallic ores in which the silicious gangue may represent a minor proportion of the ore rather than metallic and sulfide ores in which the gangue usually represents the major proportion of the ore. Representative acidic ore maform of these water-soluble terials are the feldspars, quartz, pyroxenes, the spinels, biotite, muscovite, clays, and the like.

While, as stated heretofore, the present invention is not limited to the treatment of any particular ore material, it has been found to be well suited for froth flotation of silica from phosphate rock, and this is the preferred embodiment of the invention. In the processes of removing silica from phosphate rock, the conditions are such that practically complete removal of the silica must be accomplished in order to produce a salable phosphate material. It is therefore "an advantage of this invention that our reagents not only effect satisfactory removal of the silica but are economical in'amounts used. The quantities required range from 0.1 pound to 2.0 pounds per ton of ore, depending upon the particular ore and the particular reagent. The invention is not, however, limited to the use of such quantities.

These reagents have also been successfully used for the flotation of feldspar from quartz and for the flotation of mica from quartz and calcite.

The reagents of the present invention may be used alone or in mixturesv with other promotors. They may likewise, be used in conjunction with other cooperating materials such as conditioning reagents, activators, frothing reagents, depressing reagents, dispersing reagents, oily materials such as hydrocarbon oil fatty acids or fatty acid esters. I

These new reagents are also adaptable for use in any of the ordinary concentrating processes such as film flotation, tabling, and particularly in froth flotation operations. The ore concentrating processes employed will depend upon the particular type or kind of ore which is being processed. For example, in connection with phosphate rock, relatively coarse, phosphate bearing material, for example 28 mesh and larger, can be economically concentrated by using these reagents in conjunction with other materials such as fuel oil or pine oil and subjecting to concentration by the use of tables or by film flotation employing these improved silica promoters.

When the reagents of the present invention are employed as promoters in the froth flotation of silica from phosphate rock, which is the preferred embodiment thereof, the conditions may be varied in accordance with procedures known to those skilled in the art. The reagent may be employedin the form of aqueous solutions, emulsions, mixtures, or solutions in organic solvents. such as alcohol and the like. The reagents may be introduced into the ore pulp in the flotation cell without. prior conditioning or they may be conditioned with the ore pulp prior to the actual concentration operation. They may also be stag fed into the flotation circuit.

Other improved phosphate flotation features which are known may be utilized in connection with the present invention, such as splitting the phosphate flotation feed into a plurality of size ranges and floating each size separately as described in the U. S. Patent No. 2.156.245, the very complete removal of the slime prior to flotation which is also an aid to better results as pointed out in the Erickson application Serial No. 325,011, filed March 20, 1940, and the Mead and Maust application Serial No. 320,121, filed February 21, 1940, which describes a process for classifying and desliming phosphate flotation feed by means of a hindered settling classifier and which deslimed feed is well suited for treatment in accordance with this invention.

The invention will be further illustrated by the following specific example which is an illus- Example 5 Flotation tests as follows were made on 9. Sample of Florida phosphate ore from the Old Colony mine near Brewster. This ore material which was essentially -48+200 mesh material was agitated and "scrubbed" with water to break up the clay balls. The slimes were subsequently removed by decantation and washing repeated until the ore material was substantially free of slimes.

Separate samples of the deslimed flotation feed were diluted to 20% solids with water and transferred to a laboratory size Fagergren flotation machine. The particular reagent or reagent combination was added to the pulp. The machine was started up and the pulp and reagent mixed for flve seconds. Air was then admitted to the machine and the resulting concentrate was skimmed off for three minutes. The flotation test products were then filtered, dried, weighed, and assayed. The metallurgical data obtained in these tests are presented in the table.

processes for removing the silica therefrom and the taillngs resulting from such processes are much higher in iron content than concentrates produced by the conventional soap flotation of iron minerals.

We claim:

1. In ore concentrating processes of separating acidic ore materials from other ore constituents the process which comprises carrying out the concentration operation in the presence of a substance of the group consisting of those obtained by heating a polyalkylene polyamine represented by the following general formula:

in which n, m, and z are small whole numbers, with a substance of the group consisting of naphthenic acid, talloel, higher fatty acids and higher fatty acid esters at a temperature in excess of 250 C., and salts thereof.

2. In ore concentrating processes of separating acidic ore materials from non-metallic ore concomprises carrying out the concentration operation in the presence of a substance of the group consisting of those Table Feed Concentrate Taillng Test Promoter 1 wt r Per cent Per cent Percent g g Per cent Per cent 3 3 insoi weight insol. i weight insol.

1 606. 4 64. 54 65. 20 81. 60 97. 65 34. 80 3. 59 2. Acetate of reaction product of coconut oil and ggedcpolyethylene polyamines heated to 2 602. 8 54. 54 63. 24 85. 14 98. 72 36. 76 l. 91 1. 28 Do. 3 603. 5 54. 54 71. 25 75.40 98. 2e. 75 2. 86 l. 50 Acetate of reaction product of cottonseed oil and mixed polyethylene polyamines heated tor270 C. 4 609. 0 54. 54 61. 00 88. 10 96. 92 39. 00 4. 30 3. 08 Do. 5 609. 4 54. 64 65. 95 81. 18 98. 17 34. 05 2 94 l. 83 Acetate of reaction roduct of coconut oil and diethylene tr ne heated to 270 C. l) 609. 4 54. 54 61. 95 86. 78 98. 67 38. 05 2. 06 1. 43 Do. 7 606. 5 54. 54 64. 96 83. 07 98. 94 35. 04 l. 06 l. 00 Acetate of reaction product of coconut oil and triethylene tetramlne heated to 270 C. 8 611. 4 54. 54 64. 67 83. 44 98. 94 35. 33 1. 65 1. 06 Acetate of reaction product of coconut oil and tetraothylene pentamine heated to 210 C.

1 0.50 pound per ton promoter reagent and 0.12 pound per ton pine oil added as reagents to each test. Fat used in an amount equal to the equivalent of one moi of fatty acid per mol of polyalkylene polyamlne. Fat used in an amount equal to the equivalent of two mols of fatty acid per mol of polyalkylene polyamlne.

An analysis of the metallurgical date found obtained by heating a polyalkylene polyamine in the table shows that in all tests the phosphate represented by the following general formula: product (tails) is of a satisfactory marketable E H grade. In all of the tests the phosphate product H H is of a better grade than is currently produced by H H H the flotation of phosphate particles from the quartz.

Similarly in all the tests the weight recovery of the phosphate product is much higher than would be obtained in the soap flotation of the phosphate particles. Likewise the waste product (quartz concentrate) is much higher in insoluble contents than is currently produced by the soap flotation process.

When rake classifier sands, such as those produced from the tailings at the Valley Forge Cement Company plants are treated by flotation using our reagents, the alumina in the form of mica is removed in part from the silicious material and results in a cement product having improved properties.

In the treatment of iron ore we have found that our reagents may be employed in flotation in which n, m, and a: are small whole numbers, with a substance of the group consisting of napththenic acid, talloel, higher fatty acids and higher fatty acid esters at a temperature of from about 250 C. to about 300 C., and salts thereof.

3. In the froth flotation processes of separating non-metallic ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of a substance of the group consisting of those obtained by heating a polyalkylene polyamine represented by the following general formula:

in which n, m, and x are small whole numbers,

with a substance of the group consisting of naphthenic acid, talloel, higher fatty acids and higher fatty acid esters at a temperature in excess of 250 C., and salts thereof.

4. In the froth flotation processes of separating non-metallic ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of a substance of the group consisting of those obtained by heating a Dolyalkylene polyamine represented by the following 'general formula:

n\ V H N(C,.H2n-N)=CmH2-N 11 i l '11 in which n, m, and .2: are small whole numbers, with a substance of the group consisting of naphthenic acid, talloel, higher fatty acids and higher fatty acid esters at a temperature of from about 250 C. to about 300 C., and salts thereof.

5. In the froth flotation processes of separating phosphate ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of a substance of the group consisting of those obtained by heating apolyalkylene polyamine represented by the following general formula:

in which n, m, and a: are small whole numbers,"

stance of the group consisting of those obtained by heating a polyalkylene polyamine represented by the following general formula:

in which n m, and a: are small whole numbers, with a substance of the group consisting of higher fatty acid esters at a temperature of from about 250 C. to about 300 C., and salts thereof.

7. A process according to claim 1 in which the products are used in the form of a water soluble acid addition salt.

8. In the froth flotation process of separating phosphate ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of the acetate of the product obtained by reacting coconut oil with mixed polyethylene polyamides, said polyamine containing at least three amino nitrogen atoms, to a temperature of about 270 C.

9. A process according to claim 8 in which the reagent was that obtained by employing coconut oil equivalent to one mol of fatty acid per mol of polyethylene polyamine.

10. A process according to claim 8 in which the reagent was that obtained by employing coconut oil equivalent to two mols of fatty acid per mol of polyethylene polyamine.

11. In the froth flotation process of separating phosphate ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of the acetate of the product obtained by reacting cottonseed oil with mixed polyethylene polyamines, said polyamine containing at least three amino nitrogen atoms, and heating to a temperature of about 270 C.

12. In the froth flotation process of separating phosphate ore values from acidic silicious gangue the step which comprises subjecting the ore to froth flotation in the presence of the acetate of the product obtained by reacting coconut oil with diethylene triamine at a temperature of about 270 C.

. 13. A process according to claim 12 in which the reagent employed was that obtained by employing coconut oil equivalent to one mol of fatty acid per mol of diethylene triamine.

14. A process according to claim 12 in which the reagent employed was that obtained by employing coconut oil equivalent to two mols of fatty acid per mol of diethylene triamine.

LUDWIG JACOB CHRISTMANN. DAVID WALKER JAYNE, JR. STEPHEN EDWARD ERICKSON. 

